1. Field of the Invention
The present invention relates to a digital receiver, a controlling method of the apparatus, a computer program product, and a recording medium recording thereon the product.
2. Description of the Related Art
In a digital receiver receiving a signal indicating for example audio data, an operating parameter of a circuit component which is a part of the apparatus may be changed. Published Japanese Translation No. 2001-526485 of the PCT International Publication discloses an example of such a case, and a bias current is changed as an operating parameter. According to the publication, a non-linear component of an output signal from a demodulator demodulating a signal is measured and a bias current of each amplifier stage is controlled based on the result of the measurement.
When an operating parameter such as a bias current of a circuit component is changed as in the example above, the property of the circuit component is changed and this may influence on the operation to receive a signal. For example, a change in the bias current alters the linearity of the circuit component, and this may make it impossible to properly receive an output signal if the non-linear component in the signal is large.
According to Published Japanese Translation No. 2001-526485 of the PCT International Publication, the non-linear component in the output signal is measured and the bias current is controlled in accordance with the result of the measurement. However, when the linearity of the circuit component is altered by changing the bias current, the non-linear component of the output signal from the circuit component may be suddenly changed to a large extent. Such a steep change in the non-linear component may prevent the signal from being properly received because the current control based on the result of the measurement of the non-linear component cannot be performed in time.